The present invention relates generally to internal combustion engines and more particularly to improved methods of cylinder balancing in an internal combustion engine.
Imbalance of fuel delivery quantities to cylinders in multi-cylinder engines can lead to an imbalance of power in cylinders. This variation from cylinder-to-cylinder of fuel quantity delivery may cause one, or more, cylinders to approach the knock limits of the fuel-air mixture, which ultimately can lead to performance degradation of the engine.
Spark-ignited and dual fuel internal combustion engines commonly balance cylinders via a controller collecting the measuring of the exhaust temperature of each cylinder and then adjusting an engine parameter, typically fuel quantity, spark timing or injection timing, in order to rebalance the cylinders so that the resultant cylinder exhaust temperatures more closely match each other. While this is a plausible methodology, cylinder-to-cylinder exhaust temperatures are not necessarily indicative of cylinder condition and may provide an inaccurate indication of actual cylinder conditions due to variations in (but not limited to): sensor response, sensor mounting, cylinder breathing, and the like.
Accordingly, there is an ongoing need for improving internal combustion engine operation through improved cylinder balancing.